Electrode.



K. TORNBERG.`

ELEGTBODE.

APPLICATION FILED KAB. Z7, 1911.

Patented Ma-.25,1913.

Fig. z.

Invento L VKvnfc. Tornbefg Witnesses:

bg H\s Dttorneg.

KNUT TORNBERG,

0F LYN', MASSACHUSETTS, ASSIGNOR T0 GENERAL COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC ELECTRODE.

Spcification of Letters Patent.

Patented Mar. 25, 1913.

' yapplication med March 27, 191i. serial No, 617,066.

To all whom t may concern.' Beit known that I, KNU'r TomifBEli-'ll citizen of the United States, residing `at Lynn, in the county yof Essex, State `,et Massachusetts, have invented cert-ainlainew and useful Imprdvements in-Electrodes, of which the following is a-specilication.'`

My invention," pertains to an electrode, and particularly to an electrode producing a luminous aren/upon the end of which elec trode a liquid pool is formed during normal operation.

It has hitherto beenproposed to use, as thenegative electrode, one in which the arc producing material is composed of a mixture of magnet-ite, rutile and chromite, and to inclonse this mixture in an iron shell which provides sufficient conductivity or the electrode and to make the positive e ectrode of a very slowly consuming material, forming what is known in the art as a nonconsuming electrode. Anarc formed between elcctrodes of this character is much longer than the arc formed between carbon electrodes, andpis commonly operated at a length of, about-@in inch. ,lVhen the arc is burning betvveerrelectrodes of this character, apool is formed on the negative electrode, which pool moves irregularly about its arcing face. \Under certain conditions, however, and particularly when it is required that the negative electrode should be abnormally high in titanium content and should have a smaller diameter than usual, and should at the same time be run at a higher., current than ordinarily employed, and particularly when the atmosphere is humid and hot, the tip of the electrode, cspecially during the first portion of its life, becomesvcry much rounded. Now the cath-'- ode blast issues from the negative electrode ina direction normal to the arcing surfaceof the electrode at that point, and, when the arc is burning near the edge of th'e electrode, the are is bowed outwardly and is liable to rupture altogether. When the arc has been thus ruptured, the elect-rodesare again brought into engagement, and are again separated to strike the arc; the are may then again be ruptured as before, and the process successively repeated, producing what is known in the art as jumping Furthermore, such an are, even if it is not actually ruptured, is unsteady, and a further difficulty is enctnuitered'in the use of a s negative electrode tending to` form a rounded end, in that the arc is not struck with as great certainty between such anelectrode and the non-consuming'electrode as between an electrode presenting a flat surface and a corresponding nonfeonsuniing electrode. I ,hare overcome thee defects in an electrode of thecharacter referred to by providing a second metallic shell and so arranging (he two shells that a heat insulating annulus is formed between them.

a For a fuller understanding of my invention, reference is had to the accolr'ipanying drawings, in which-V+ f i Figure 1 is a longitudinal section of inv electrode and Figf 2 is ysirhilar to Fig. 1 but with the are forming material omitted to more clearly show the structure ofthe shells.

In these drawingsiil,,indicates an outer metallic shell preferably of iron'which may he closed at its lower-"end by a thimble 2 in the usual manner.v An inner shell 3 is pro'- vided with applurality of protuberances 4 which may befconvcniently arranged in a series of vertical rows, the protuberances of Vadjacent rows bein arranged in staggered' relation to each etici: thus provided between the outer and inner shells which serves to thermally insulate the outer shell from Athe inner one` The upper end of the inner tube is provided with a seal 8.- In Fig. 1, the inner shell Bis show n illcd with a luminous arc material such as the magnetite mixture above noted, which is held within the shell by a seal 8, while in Fig. 2 the same structure is disclosed but without the fillingr niixturef It will thus be seen that a heat v'insulating annulus, which,

in the example illustrated, is a layer of all,

is formed between the outer and'innc': shells. lf desired, a wire 't' placed between thcouter and inner-shells at the end of the electrode and a bead 9 formed on the inner-'shell at the opposite end of the electrode may assist in maintaining the two shells in spaced rela-- tion.

My theory of the reason for the double shells ovcrcon'iing the defects hitherto noted. in electrodes of the character described is that the portion of the elect roder tronil which the arc burns should be kept at a high teniperature, and this is accomplished hy the second shell and the thermal insulating annulus between the two. found that two such shells, willi a heat in- At any rate, l have,

An air Space 5 is* i sulaml 'end which becomesA rounded during operaaccomplishesv the desired object.

'\.\'.i.i1;, uffV j Wliil' 'ilavein'eni ne vgn lite, ifu'til'e" 'and ohromite :1s 1 suiilleelectrode composition, my inventio'n Ais nel: limitedv i0 ,thesematerials but 'may be used in `any electrodel inv which liquid 'pool is formedupon the lV-h'at I-clzii'm as new, 'and desire to secure by Letters P11-teni; -ojlhe Uniied States; is, L An are light- -electrode compoed of va material yielding 'u luminous arf springing from {1 -molten pool, inelosed wfifnin a metallic` shell, said shell bein'gxsurrounded by 'a second shell the inter-unl diameter ofwhic'hV is greater' than -tlielexiern'all diameter of the outer shell, and means .for maintaining said shells in spaced relation `so that; an airspace is provided between the two'shells.

2. An arc light electr'odecomposed of a material yielding a luminous arc springing li'c shell provided with outwardly exiend- 25 jing and uniformly. spaced `protuherermes,

)finden .outei` shell lembracing he first and in frictionalen'gagement. .with said protub erances4 l 3. An arc light electrode composed of a material yielding a luminous are springing from afmolten pool., inclosed Within a melallic shell having its wall indented from Within at a plurality of points (no formcg'aA4 series of outwardly exfendi'n 'xotuber# 35 ences, and an outer shell embbing 'thelirst 'and in frictonal'oontact with-the-said pro: A l tuberances, whereby an nixnula'i; air fs'pa'-v-- formed between fthe .two shells.

In witnesswhereof, I hve her'e 'ntosell my hand this'tw'enty third day ofMariY-li,

JOHN A. MGMANS; Jr.,A CHARLES A. BARNAxiDg- 

